It is often necessary to rigidly hold and support a contoured part during machining. A separate fixture is needed for each part due to the complex contours involved. Large costs are involved in creating, altering, and storing and setting up customized fixturing.
It would be desirable to have a single fixture which can support different contoured workpieces reliably and effectively.
The following U.S. patents are noted as bearing in a general way on the subject matter of the present invention: 2,729,040; 3,108,791; 3,821,867; 3,765,359; 4,034,517; 4,066,249; 4,088,312 and 4,200,271.
The U.S. Pat. No. 2,729,040 discloses a vacuum jig for holding contoured sheet parts. It requires a spring metal chuck carrying plate which flexes to specific contours. This requirement severely limits the possible contours which may be generated. This jig will not accept parts with small radius curves nor will it accept parts with inflective curves. This jig also requires a vacuum sealing flange around the entire part periphery. Such a flange limits the size and peripheral shape of the parts which may be held. The U.S. Pat. No. 2,729,040 does not provide for automatic indexing nor a consistent means of locating a part on the contour.
The U.S. Pat. No. 4,088,318 discloses a spring-biased system which utilizes diaphragms and V-blocks to clamp its rods in place. It utilizes vacuum in conjunction with the rods. However, the vacuum is applied to all the rods in every instance. It is not, therefore, very flexible.